A psychological evaluation of the Las Vegas gunman's criminal father could offer clues about the shooter's psyche

Benjamin Hoskins Paddock, the father of Route 91 music festival gunman Stephen Paddock, is seen in an undated photo from the FBI's Most Wanted Fugitives archives. Courtesy FBI/Handout via REUTERS News clues into the life of the father of the man accused of killing 58 people during a concert in Las Vegas could help answer questions about why Stephen Paddock committed what is considered the biggest mass shooting in modern American history.

A psychiatric evaluation from 1960 exposes the bizarre behavior of Benjamin Paddock, Stephen's father, as he faced questions about his fitness to stand trial for a series of crimes, including stealing cars, robbing banks, and committing fraudulent financial transactions, according to The New York Times.

During his psychiatric examination, the elder Paddock chain-smoked and smiled often as the psychiatrist, William B. McGrath, asked him questions. By the end of the doctor's interview, he concluded that Benjamin "enjoys being an interesting subject of examination" and had a "sociopathic personality."

Bejamin described himself as a "third time loser" and "alert psychotic," expressed no remorse for his crimes, and claimed to have a genius IQ.

Despite Benjamin's odd behavior during questioning and occasional boasting of his criminal exploits, McGrath ultimately ruled Paddock fit to stand trial. He also revealed that Paddock had no prior history of mental illness.

Stephen similarly had no recorded history of mental illness that would explain why he decided to shoot at concertgoers in Las Vegas almost two weeks ago, but investigators are trying to piece together any evidence that might suggest a motive.

His father's history could offer some valuable insight.

When Stephen was just seven years old, his father vanished from his life after FBI agents arrested him at his home. After escaping from a federal penitentiary in the late 1960s, the FBI placed him on its Most Wanted list.

Stephen, contrary to his father, had no criminal history prior to the shooting, according to authorities. He was "reserved, even boring," the Times noted in its report, although he was known to be a serial gambler.

Authorities are still searching for a motive for the Las Vegas shooting.